Getting patients to improve the way they eat and move more can be notoriously challenging. But there is strong evidence that encouraging patients to embrace healthier lifestyles may have a major impact on their health. 

A new report by the World Cancer Research Fund/American Institute for Cancer Research (AICR) analyzed a wide range of research and concluded that nutrition and physical activity directly contribute to more than a dozen types of cancer. The AICR estimates that at least 40% of cancers are lifestyle-related.

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But for physicians, getting patients to commit to healthy lifestyles is not easy. In 2015, the Journal of Biomedical Education analyzed the state of nutrition training among doctors. They found that medical schools average about 19 hours of nutrition training, with one-third of responding schools requiring 12 or fewer hours and 12 requiring none.

“There’s no doubt that medical professionals need to pay more attention and start applying the research that’s out there,” said Nigel Brockton, PhD, Director of Research for AICR. “Every generation has one thing where they wonder why they did something—like not wearing seat belts—and I can’t help but think one day we’ll look back and wonder why we were putting all of that stuff in our mouths?”

The research

The goal of the joint project was to arrive at a consensus about the link between nutrition, exercise, and cancer based on current research. Here are some of the findings:

·      Being overweight or obese causes 12 types of cancer, including endometrial, ovarian and pancreatic.

·      Alcohol consumption is linked to 6 cancers, including breast, mouth, and liver cancer, even when consuming 1 small glass daily.

·      Being physically active is protective against endometrial, breast (post-menopause), and colorectal cancers.

·      A healthy diet is generally associated with a reduced risk of cancer.

·      A healthy weight and good physical activity can increase survival rates and improve treatment outcomes – particularly among breast cancer patients.


Dr Brockton said the group focused on diet mainly because of its amorphous nature. Physical activity can be measured by time and intensity. Body mass index is also a simple measurement. But every patient is going to translate eating a “healthy diet” differently.

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Even though the report is vast, the recommendations are straightforward and not at all earth-shattering.

“We want to move people toward a diet that is characteristic of good health,” Dr Brockton said. “They should eat lots of fruits and vegetables, healthy carbs, and beans.”

Beyond that, they encourage limiting consumption of fast food and processed foods, and reducing intake of starches, sugars, alcohol, and red meat. They also recommend eating “little, if any” processed meat, which has been tied to an increased risk of colorectal cancer. 

“Our recommendations are pretty pragmatic,” he said. “While we say avoid processed meat, a hamburger a couple of times a year at a ball game won’t give you cancer. It’s the chronic overconsumption of these things we recommended against.”

Joanne K. Gardner, a dietitian/nutritionist with Duke Integrative Medicine in Durham North Carolina, commends AICR for their guidelines and urges physicians to encourage patients to embrace habits that protect against cancer.

“We have choices every day we are going to make,” Gardner said. “Are people bringing a snack of fruit and yogurt and nuts to work or reaching for a candy bar and bag of chips?”


Nearly one-third of the US population is overweight or obese, with excess weight the main preventable cancer risk factor, so physicians also need to address exercise. “Weight is the most important factor, and then physical activity, and then what we are eating,” when it comes to cancer prevention and recurrence,” said Erika Connor, a registered dietitian with Stanford Cancer Institute.

Dr Brockton said the AICR recommendations are straightforward: move more, sit less. Patients should aim for 150 minutes of physical activity a week. This is in line with recommendations from the American Cancer Institute and the American College for Sports Medicine’s guide for cancer survivors. (They recommend following the federal government’s “Physical Activity Guidelines for Americans.”) The recommendations call for 150 minutes a week of moderate-intensity or 75 minutes of vigorous-intensity physical activity weekly. This should include muscle strengthening twice weekly and stretching on other days.

Putting it into practice

Connor emphasizes that patients pay attention to what physicians say. While this is good, she notes this can also be problematic. “A lot of my patients have physicians who tell them they can eat whatever they want,” she said. “Patients translate that into thinking they can have pizza and burgers because it doesn’t matter … They don’t think ‘eat however many fruits and veggies I want.’” She has had patients call her on their way home from the hospital right after surgery asking what they can eat at McDonald’s. She tells them to keep driving.

Gardner and Connor recommend a simple guideline to offer patients: aim for 3 servings (a half cup) of fruit and 5 servings of vegetables daily. If patients eat more healthy foods, they will have less room for the unhealthy stuff, Connor said.

Another strategy may be to suggest to patients a single small, measurable goal to change at a time, such as reducing calorie-laden drinks, taking lunch to work, or not eating after 8 p.m. Connor tells patients to cut out side dishes, such as the burger without the fries or the sandwich without the potato chips. “They don’t need to eat everything when they go out … because it’s the ‘everything’ that is getting them into trouble,” she said.